v4.19.13 snapshot.
diff --git a/include/linux/timekeeper_internal.h b/include/linux/timekeeper_internal.h
new file mode 100644
index 0000000..7acb953
--- /dev/null
+++ b/include/linux/timekeeper_internal.h
@@ -0,0 +1,151 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * You SHOULD NOT be including this unless you're vsyscall
+ * handling code or timekeeping internal code!
+ */
+
+#ifndef _LINUX_TIMEKEEPER_INTERNAL_H
+#define _LINUX_TIMEKEEPER_INTERNAL_H
+
+#include <linux/clocksource.h>
+#include <linux/jiffies.h>
+#include <linux/time.h>
+
+/**
+ * struct tk_read_base - base structure for timekeeping readout
+ * @clock: Current clocksource used for timekeeping.
+ * @mask: Bitmask for two's complement subtraction of non 64bit clocks
+ * @cycle_last: @clock cycle value at last update
+ * @mult: (NTP adjusted) multiplier for scaled math conversion
+ * @shift: Shift value for scaled math conversion
+ * @xtime_nsec: Shifted (fractional) nano seconds offset for readout
+ * @base: ktime_t (nanoseconds) base time for readout
+ * @base_real: Nanoseconds base value for clock REALTIME readout
+ *
+ * This struct has size 56 byte on 64 bit. Together with a seqcount it
+ * occupies a single 64byte cache line.
+ *
+ * The struct is separate from struct timekeeper as it is also used
+ * for a fast NMI safe accessors.
+ *
+ * @base_real is for the fast NMI safe accessor to allow reading clock
+ * realtime from any context.
+ */
+struct tk_read_base {
+ struct clocksource *clock;
+ u64 mask;
+ u64 cycle_last;
+ u32 mult;
+ u32 shift;
+ u64 xtime_nsec;
+ ktime_t base;
+ u64 base_real;
+};
+
+/**
+ * struct timekeeper - Structure holding internal timekeeping values.
+ * @tkr_mono: The readout base structure for CLOCK_MONOTONIC
+ * @tkr_raw: The readout base structure for CLOCK_MONOTONIC_RAW
+ * @xtime_sec: Current CLOCK_REALTIME time in seconds
+ * @ktime_sec: Current CLOCK_MONOTONIC time in seconds
+ * @wall_to_monotonic: CLOCK_REALTIME to CLOCK_MONOTONIC offset
+ * @offs_real: Offset clock monotonic -> clock realtime
+ * @offs_boot: Offset clock monotonic -> clock boottime
+ * @offs_tai: Offset clock monotonic -> clock tai
+ * @tai_offset: The current UTC to TAI offset in seconds
+ * @clock_was_set_seq: The sequence number of clock was set events
+ * @cs_was_changed_seq: The sequence number of clocksource change events
+ * @next_leap_ktime: CLOCK_MONOTONIC time value of a pending leap-second
+ * @raw_sec: CLOCK_MONOTONIC_RAW time in seconds
+ * @cycle_interval: Number of clock cycles in one NTP interval
+ * @xtime_interval: Number of clock shifted nano seconds in one NTP
+ * interval.
+ * @xtime_remainder: Shifted nano seconds left over when rounding
+ * @cycle_interval
+ * @raw_interval: Shifted raw nano seconds accumulated per NTP interval.
+ * @ntp_error: Difference between accumulated time and NTP time in ntp
+ * shifted nano seconds.
+ * @ntp_error_shift: Shift conversion between clock shifted nano seconds and
+ * ntp shifted nano seconds.
+ * @last_warning: Warning ratelimiter (DEBUG_TIMEKEEPING)
+ * @underflow_seen: Underflow warning flag (DEBUG_TIMEKEEPING)
+ * @overflow_seen: Overflow warning flag (DEBUG_TIMEKEEPING)
+ *
+ * Note: For timespec(64) based interfaces wall_to_monotonic is what
+ * we need to add to xtime (or xtime corrected for sub jiffie times)
+ * to get to monotonic time. Monotonic is pegged at zero at system
+ * boot time, so wall_to_monotonic will be negative, however, we will
+ * ALWAYS keep the tv_nsec part positive so we can use the usual
+ * normalization.
+ *
+ * wall_to_monotonic is moved after resume from suspend for the
+ * monotonic time not to jump. We need to add total_sleep_time to
+ * wall_to_monotonic to get the real boot based time offset.
+ *
+ * wall_to_monotonic is no longer the boot time, getboottime must be
+ * used instead.
+ */
+struct timekeeper {
+ struct tk_read_base tkr_mono;
+ struct tk_read_base tkr_raw;
+ u64 xtime_sec;
+ unsigned long ktime_sec;
+ struct timespec64 wall_to_monotonic;
+ ktime_t offs_real;
+ ktime_t offs_boot;
+ ktime_t offs_tai;
+ s32 tai_offset;
+ unsigned int clock_was_set_seq;
+ u8 cs_was_changed_seq;
+ ktime_t next_leap_ktime;
+ u64 raw_sec;
+
+ /* The following members are for timekeeping internal use */
+ u64 cycle_interval;
+ u64 xtime_interval;
+ s64 xtime_remainder;
+ u64 raw_interval;
+ /* The ntp_tick_length() value currently being used.
+ * This cached copy ensures we consistently apply the tick
+ * length for an entire tick, as ntp_tick_length may change
+ * mid-tick, and we don't want to apply that new value to
+ * the tick in progress.
+ */
+ u64 ntp_tick;
+ /* Difference between accumulated time and NTP time in ntp
+ * shifted nano seconds. */
+ s64 ntp_error;
+ u32 ntp_error_shift;
+ u32 ntp_err_mult;
+ /* Flag used to avoid updating NTP twice with same second */
+ u32 skip_second_overflow;
+#ifdef CONFIG_DEBUG_TIMEKEEPING
+ long last_warning;
+ /*
+ * These simple flag variables are managed
+ * without locks, which is racy, but they are
+ * ok since we don't really care about being
+ * super precise about how many events were
+ * seen, just that a problem was observed.
+ */
+ int underflow_seen;
+ int overflow_seen;
+#endif
+};
+
+#ifdef CONFIG_GENERIC_TIME_VSYSCALL
+
+extern void update_vsyscall(struct timekeeper *tk);
+extern void update_vsyscall_tz(void);
+
+#else
+
+static inline void update_vsyscall(struct timekeeper *tk)
+{
+}
+static inline void update_vsyscall_tz(void)
+{
+}
+#endif
+
+#endif /* _LINUX_TIMEKEEPER_INTERNAL_H */